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This contribution explores synthetic routes adopted and optimized for the preparation of three new hexatopic tripodal organic ligands designed for Ln(III) complexation. In these ligands, three strands bearing two pyridyldicarbonyl binding moieties are anchored with a small aliphatic triamine. The described synthesis is not straightforward and depends on the nature of the spacer between coordinating moieties. In addition to the characterisation of targeted ligands, the structure of ditopic intermediates is assessed by X-ray crystallography and discussed with respect to the spacer nature.
Herein, we report on the rational design, preparation and characterization of a novel homo-octanuclear helicate, which results from a spatial extension of the central tetranuclear platform. The 3D supramolecular assembly is obtained by complexing europium(III) with a new hexatopic tripodal ligand. The isolated octanuclear helicate is fully characterized by different methods clearly evidencing the structure predicted with molecular modelling. The ligand preorganization plays a crucial role in a successful self-assembly process and induces the formation of a well-defined triple-stranded helical structure. This prototypal octanuclear edifice accommodating functional lanthanides within a 3D scaffold offers attractive perspectives for further applications.